Exact solution of electric transitions and production probability of isomer state of FP

Wada, Hiroaki

This report describes the study done within the period of time when I was postdoctoral research worker at Japan Nuclear Cycle Development Institute. The report includes two parts as follows. (1) Exact Solution of Electric Transitions for High Energy photons. Technologies for creating high-energy beams have been rapidly developed. These advancements make the research using high-energy -rays more important. The electric transition rates for high-energy -rays were formulated. The electric multipole fields were treated strictly in the process of calculating the electric transition rates and the nuclear states were taken as the harmonic oscillator wave functions. (2) Production of the isomeric state of Cs in the thermal neutron capture reaction Cs(n, )Cs. In order to obtain precise data of the neutron capture cross section of the reaction Cs(n, )Cs, the production probability of isomer state Cs was measured in this work. The 1436 keV -ray emitted from both of Cs and Cs was measured. A production ratio of Cs to (Cs and Cs) was deduced from time dependence of peak counts of 1436keV -ray. The probability of the production of CS was obtained as 0.750.18 and this value revised the effective cross section upwards 92%. The effective cross section and the thermal neutron capture cross section were obtained as =0.290.02 b and =0.270.03 b with taking into account the production of Cs.